At present, in a production line of a liquid crystal display (LCD), a cell alignment device usually identifies tags in an array substrate and a color filter substrate, and thus aligns the two substrates. However, one problem is that the temperature changes greatly during a film forming procedure of each layer in the array substrate and the color filter substrate. This results in large offsets of the tags in the array substrate and the color filter substrate from respective positions.
That is to say, the cell alignment device mainly achieves alignment of the array substrate and the color filter substrate by identifying tags in the two substrates. Therefore, when respective tags of the array substrate and the color filter substrate have been offset, the device will not be able to perform alignment accurately. In this case, cell alignment can be barely achieved by using algorithms of the device per se, but high accuracy of cell alignment cannot be guaranteed. Accordingly, this will often lead to defects such as light leakage and color shift of the display panel after cell alignment.